Beam structure for mine shaft



Oct- 2, 19 2 c. F. B. VAN WYK BEAM STRUCTURE FOR MINE SHAFT Filed NOV. 24, 1959 W a m N W 3,056,266 BEAM STRUCTURE FOR MINE SHAFT Christiaan F. B. van Wyk, Northclif't' View, Johannesburg,

Transvaal, Union of South Africa, assignor to Wright Anderson (South Africa) Limited, Klipfontein, Boksburg North, Transvaal, Union of South Africa Filed Nov. 24, 1959, Ser. No. 855,195 Claims priority, application Union of South Africa May 15, 1959 1 Claim. (Cl. 61-41) This invention relates to beams or buntons used for building up a supporting structure for skip and cage guides in mine shafts of a type which are used for ventilation purposes in addition to providing means for access to and from the mine.

It is well known that where rolled steel beams of conventional cross-sections are used for building up such supporting structures they offer considerable resistance to the ventilation air flow through the shaft with consequent wastage of power necessary to move the air through the shaft. The attachment of a streamlined shrouding to the beams has been proposed but is not a wholly acceptable solution to the problem due to the difficulty of attachment of the shrouding and also due to the displacement and wear of the shrouding.

It is accordingly an object of this invention to provide a beam and supporting structure built therewith which while providing adequate strength will also otfer a low resistance to the air flow without necessity for the use of a shroud or like streamlined covering.

In accordance with this invention there is provided a beam or bunton comprising a pair of steel strips of equal Width each having the portions adjacent both longitudinal edges bent inwardly and said longitudinal edges abutted and welded together to form an elongated hollow hexagonal structure in cross-section.

In accordance with a further aspect of the invention, there is provided a supporting structure for skip guides built up of beams of the type defined above.

The invention is illustrated in the accompanying drawings in which:

FIG. 1 is an end elevation of a bunton,

FIG. 2 illustrates a method of connecting a pair of said buntons at right angles to each other, and

FIG. 3 is a plan view of a supporting structure built up of said buntons.

As shown in FIG. 1 the bunton 1 in section or end elevation consists of an elongated hexagonal structure built up from two steel strips 2, the parallel portions 3 on each side of the longitudinal central area of the said strips 2 being bent inwardly and the edges 4 abutted such that a V-shaped groove 5 is formed between them. These abutting edges 4 are then Welded together, sufficient weld metal 6 being run into the groove 5 formed by the abutting edges so that an external rounded surface may be formed by grinding or otherwise.

The dimensions of the buntons 1 are important in order to obtain the necessary structural strength with maximum possible streamlining. As an example the buntons may be built up from a pair of 6 steel strips 2 having a height of about 17" and length corresponding to that of the required beam. A strip of about 4 /2" width adjacent each longitudinal edge 4 is then bent inwardly through an angle of about 20 and the longitudinal edges of the strips 2 abutted and welded together. In all cases the welding of the bunton on opposite sides of a longitudinal centre line will result in minimum distortion so that no straightening operation will normally be required after welding.

A supporting structure is built up with the beams in the ventilation shaft by welding plates 7 onto the ends of at htates atent O ice least some of the buntons 1 and bolting these plates 7 to the sides of other buntons. The plates 7 are longer than the cross-sectional Width of the buntons 1 to which they are welded so that they form flanges 8 projecting on each side of said buntons. These flanges 8 are suitably drilled for insertion of the bolts 9 as shown in FIG. 2.

Corresponding holes are drilled through the sides of the buntons to which the flanges 8 are to be secured, and cylindrical spacers 10 welded into position to extend between the corresponding hole in the opposite sides of the buntons. The bolts 9 fit through these spacers 10 which act to prevent collapse when the bolts are tightened, of the buntons in which th spacers 10 are fitted.

In certain cases where a tie is merely required between adjacent buntons instead of a load bearing member, a bunton of smaller dimensions than the buntons 1 but also having drilled end flanges 12 may be used as shown in FIG. 3, said flanges 12 being bolted in position in a manner similar to the bolting of flanges 8. Skip guides 13 are secured in position in a similar manner.

The ends of the buntons 1 to be secured to the rock face of the shaft or the concrete lining thereof, may be grouted in position in suitably formed pockets. Alternatively as shown in FIG. 3 flanges 14 inclined at suitable angles are welded to the ends of the buntons 1 and secured to the shaft wall 15 or liner by expandable bolts or the like accommodated in suitably drilled holes. It will be noted that in the circular shaft illustrated the central bunton 1 is located at one side of the shaft diameter to facilitate the locating of the bunton in position.

It will be appreciated that the exact form of the supporting structure built with the bunton 1 will vary depending on requirements but in all cases the buntons are positioned with their longest cross-sectional dimensions in line with the length of the shaft and normally vertical, so that they offer the minimum resistance to air flow through the shaft. The reduction in resistance to air flow is very considerable as compared to the normal rolled steel beams or joists and can for example, in a shaft seven thousand feet deep be in excess of 50%, resulting in a corresponding reduction in both the capital cost of ventilation equipment required and in the running costs of the equipment.

In addition to offering this low resistance to air flow, the structure is to some extent resilient, tending to absorb any shocks due to a skip traversing irregular portions of the skip guide, while at the same time providing all the strength necessary for supporting the guides, and the shape of the buntons will assist in deflecting falling objects.

What I claim as new and desire to secure by Letters Patent is:

A strip guide supporting structure for mine shafts subject to forced ventilation, said structure comprising a shaft wall, horizontally spaced steel buntons extending r transversely of the shaft and adapted for securement of the guides thereto, said buntons being each of hexagonal cross-section considerably flattened so that its longer axis extends vertically with its more acute apices directed in accordance with the air flow through the shaft, and with two fiat parallel sides which bound the smaller dimension of the bunton extending parallel with the direction of air flow, each of said buntons comprising a pair of elon gated steel strips of equal width, the intermediate portions of the strips being in spaced parallel relationship, marginal portions at each side of said strips being bent inwardly toward the corresponding portions of the opposite strip and with the respective longitudinal edges of the strips at each side in continuous contact, welding affording continuous nonprotruding connecting means at the apices formed at said contacting edges, the structure thus comprising an elongated hollow strut of uniform hexagonal cross-section throughout its length, means provided for rigidly securing two or more of said buntons together, said means including registering holes bored through the parallel spaced intermediate portions of the strips comprising the buntons, tubular spacer elements extending between said portions of the strip and co-axial with pairs of said registering holes, abutment plates secured to an end of certain of the buntons and having holes therein, and fastening elements passing through said registering holes and tubular spacers of the first named buntons and through the holes in the plates secured to the second named buntons.

References Cited in the file of this patent UNITED STATES PATENTS 844,944 Jacobs Feb. 19, 1907 4 Scholz Oct. 24, 1911 McClure Feb. 18, 1919 Lee et al Sept. 13, 1927 Henderson Mar. 28, 1939 Ulrich Aug. 24, 1943 Blickensderfer et al. May 7, 1946- Parkes Aug. 17, 1948 Voltz et al July 10, 1956 Logan July 30, 1957 FOREIGN PATENTS Germany 1952 

